Vitamin D Levels in Subjects With and Without Type 1 Diabetes Residing in a Solar Rich Environment

Abstract

Objective- Previous studies, largely in Northern Europe, have suggested an association between type 1 diabetes (T1D) and reduced serum 25(OH)-vitamin D levels; a concept we tested in individuals residing in a solar rich region (Florida, USA).

Research design and methods- Serum samples from 415 individuals residing were cross-sectionally analyzed 153 controls, 46 new-onset T1D patients, 110 established T1D patients (samples ≥ 5 months from diagnosis), and 106 of their first-degree relatives.

Results- 25(OH)-vitamin D levels (median ng/ml; range; IQR) were similar amongst controls (20.1; below detection (bd)-163.5; 13.0-37.4), new-onset T1D patients (21.2; bd-48.6; 12.2-30.2), established T1D patients (23.2; bd-263.8; 13.8-33.9), and first-degree relatives (22.15; bd-59.9; 12.7-33.1) (P=0.87). Mean 25(OH)-vitamin D levels were less than the optimal WHO level of 30 ng/ml in all study groups.

Conclusions- Reduced serum 25(OH)-vitamin D levels were not specifically associated with T1D. The uniform suboptimal 25(OH)-vitamin D levels, despite residence in a zone with abundant sunshine, support additional dietary vitamin D fortification practices.